Intense heat from the sun, snow and ice, road oils and windshield washer solvents can cause rubber wiper refills to deteriorate. It is recommended to replace the refills twice a year or when streaking or chattering occurs. To maintain effectiveness and prolong element life, keep the windshield and wiper blades clean by washing with a glass cleaner and wiping the rubber blades. Avoid moving the wipers by hand to prevent damage. To inspect or replace the wiper blade elements, place the wiper switch in LOW speed and the ignition switch in ACC position. When the blades are vertical, turn the ignition switch OFF. Cracked, broken, or torn elements should be replaced immediately. Replacement intervals vary, but ozone deterioration limits element life to about one year. If the wiper pattern is smeared, streaked, or chattering, replace the elements in pairs. Aftermarket blades may require different types of refills. Anco® refills have a release button, Trico® refills can be removed by pressing down on the metal backing strip, and other Trico® refills have two metal tabs that need to be squeezed together. Polycarbonate refills have a locking device, and Tridon® refills require removing the wiper blade by twisting counterclockwise. Follow the manufacturer's instructions closely and ensure all frame jaws are engaged to avoid scratching the glass during wiper operation.